The present invention relates to a construction machine equipped with an engine and a plurality of cooling units, in which some of the cooling units are disposed in parallel and cooled with a single cooling fan in order to enhance the cooling efficiency, reduce the leakage of operation noise, and facilitate the cooling of the cooling units.
Construction machines include, for example, a hydraulic shovel that performs a digging operation for a dam, a tunnel, a road, water supply and drainage, etc., or a dismantling operation for constructions, etc.
The hydraulic shovel is constructed of a lower travel body, an upper swivel body supported on the lower travel body so that it can swivel, and a working unit provided on the front portion of the upper swivel body.
The upper swivel body is usually provided with a driver""s cab. However, there are cases where small hydraulic shovels have not a driver""s cab but a driver""s seat.
Furthermore, the frame of the swivel body is provided with an engine, a hydraulic pump, cooling units, batteries, control valves, a fuel tank, a working-oil tank, etc.
The construction machine performs various operations such as traveling by the lower travel body, swiveling by the upper swivel body, digging by the working unit, etc. These operations are performed by a hydraulic actuator, constructed of a hydraulic motor, a hydraulic cylinder, etc. As shown in FIG. 11, pressure oil is supplied to the hydraulic actuator by the hydraulic pump 05 that is driven by the engine 03.
In addition, units, such as the engine 03, radiator 06, hydraulic pump 05, and direction-switching valves for switching the direction of the pressure oil supplied from the hydraulic pump 05, are disposed within the upper swivel body.
The upper swivel body is provided with an engine room 02 having a cover 01. Within the engine room 02, the engine 03 is provided, and the radiator 06 for cooling the engine 03, an oil cooler 010 for cooling working oil, an intercooler 08 for cooling air which is supplied to the combustion chamber of the engine 03, and a condenser 012, are disposed.
The intercooler 08, oil cooler 010, radiator 06, and condenser 012 constitute a first cooling unit group R which is used to cool working oil and cooling water. To expose the first cooling unit group R to cooling air and then cool the coolants of the first cooling unit group R, a cooling fan 014 is disposed. The cooling fan 014 is driven by the engine 03.
The cover 01 that constitutes part of the engine room 02 is provided with outside-air introducing ports 01a for introducing the outside air, and exhaust ports 01b for discharging the introduced air. The introduced air cools the first cooling unit group Rand then the engine 03, the hydraulic pump 05, and the direction switching valves. Thereafter, the air that has reached high temperature is discharged from the exhaust ports 01b to the outside.
With this arrangement, cooling air is introduced through the outside-air introducing ports 01a. Within the engine room 02, a flow of air occurs as indicated by arrows, cools the engine 02, the hydraulic pump 05, the direction switching valves, etc., and is discharged from the exhaust ports 01b. 
As shown in FIG. 11, with respect to the first cooling unit group R provided within the engine room 02, the cooling air flows in the order of condenser 012, intercooler 08, oil cooler 010, and radiator 06 from the upstream side.
The intercooler 08 is used for cooling air compressed by a supercharger 016 that increases the pressure of the fuel-air mixture in the engine 03. Because of this, a filter unit 017 is provided on the exterior of the engine room 02 to prevent the entry of dust and dirt.
The supercharger 016 is used to compress introduced air by rotating the turbine with the energy of the exhaust gas of the engine 03. Since the temperature of the introduced air rises due to adiabatic compression, it is necessary to cool the introduced air before it is supplied to the engine 03, for the output of the engine 03 and purification of the exhaust gas.
The introduced air is cooled by the intercooler 08, and is generally cooled to about 40 to 70xc2x0 C. at the normal temperature.
Since the coolant of the intercooler 08 has to be cooled to a temperature lower than those of other heat exchangers, and the quantity of the radiant heat of the oil cooler 010 and the radiator 06 is relatively large, the intercooler 08 is generally disposed on the most upstream side of a flow of air, or on the upstream side from the radiator 06.
Since the supercharger 016 must be disposed on a portion of the engine 03, conduits 018, 019 for circulating compressed air are connected between the supercharger 016 and the intercooler 08 and between the intercooler 08 and the engine 03.
For the aforementioned reasons, the aforementioned heat exchange is performed in the order of condenser 12, intercooler 08, oil cooler 010, and radiator 06, and in order to enhance the cooling efficiency, the condenser 12, the intercooler 08, the oil cooler 010, and the radiator 06 are disposed in close proximity to one another. However, in construction fields, dust and dirt tend to adhere to the condenser 012, the intercooler 08, the oil cooler 010, and the radiator 06. If dust and dirt adhere to the condenser 012, the intercooler 08, the oil cooler 010, and the radiator 06, the aforementioned various operations cannot be continued unless they are frequently cleaned.
In the case where the intercooler 08, the oil cooler 010, and the radiator 06 are disposed in the recited order, there are cases where, in a narrow space within the engine room 02 of the hydraulic shovel, particularly a narrow space within the engine room of a small hydraulic shovel, rotation of the oil cooler 010 becomes difficult. In the case where the intercooler 08 is disposed so as to face the oil cooler 010 or radiator 06, the intercooler 08 becomes a hindrance and therefore the oil cooler 010 cannot be cleaned.
Hence, the radiator 06 or oil cooler 010 is made of a lightweight aluminum alloy so that it can be easily lifted upward. The radiator 06 or oil cooler 010 is first lifted upward to form an open space behind the intercooler 08. Then, the intercooler 08 is cleaned, for example, with an air jet nozzle. The removed radiator 06 or oil cooler 010 is also cleaned, and is returned to the original position.
Because the air suction and exhaust tubes of the intercooler 08 are large in diameter and are generally fixed on the upper swivel body, the aforementioned operation becomes necessary.
In addition, in the conventional construction machine shown in FIG. 11, the first cooling unit group R, the engine 03, and the hydraulic pump 05 are disposed in a cooling-air passage which is widely communicated through a core having the area of the wide cooling-air passage of the cooling units within the engine room 02. Therefore, there is a fear that noise generated by the engine 03 and the cooling fan 014 will be transmitted from the wide area to the outside.
In the conventional construction machine, if the first cooling unit group R is not cleaned, the cooling fan 014 will be clogged by dust and dirt. As a result, the circulation of the cooling air for the first cooling unit group R is reduced and the cooling efficiency becomes low. Because of this, the performance of the construction machine cannot be sufficiently utilized. In addition, to clean the radiator 06 or oil cooler 010, removing and installing the radiator 06 or oil cooler 010 require labor and time, resulting in a reduction in the operation efficiency. Furthermore, as described above, there is a fear that noise will be transmitted to the outside of the construction machine.
The present invention has been made in view of the problems mentioned above. Accordingly, it is the primary object of the present invention to provide a construction machine that is capable of easily cleaning the cooling units, enhancing the cooling efficiency, and reducing noise. The construction machine is equipped with a first cooling unit group consisting of a plurality of cooling units, and a second cooling unit group where some cooling units in the first cooling unit group are disposed in parallel. The remaining cooling unit of the first cooling unit group is disposed with a gap between itself and the second cooling unit group, or is disposed in parallel with the second cooling unit group. The construction machine is further equipped with a cooling fan disposed so that it faces the cooling units disposed as described above.
To achieve the object of the present invention mentioned above, there is provided a first construction machine comprising: a nearly sealed engine room section where an engine is disposed; a first cooling unit group comprising a plurality of cooling units; and a single cooling fan for cooling a second cooling unit group where some cooling units of the first cooling unit group are disposed in parallel; wherein the second cooling unit group and the cooling fan are disposed so that they face each other.
With this arrangement, cleaning of the cooling units can be easily performed and the cooling efficiency can be enhanced. In addition, the leakage of engine noise can be reduced.
In accordance with the present invention, there is provided a construction machine comprising: a first cooling unit group comprising a plurality of cooling units; a cooling fan for cooling a second cooling unit group where some cooling units of the first cooling unit group are disposed in parallel; an engine; a partition member provided between the cooling fan and the engine; a chamber, partitioned and formed by the partition member, where the first cooling unit group and the cooling fan are disposed; and a nearly sealed engine room section, partitioned by the partition member, where the engine is disposed; wherein the cooling fan comprises a single cooling fan.
With this arrangement, cleaning of the cooling units can be easily performed. In addition, the leakage of engine noise can be reduced and the cooling efficiency can be enhanced.
In the first and second construction machines of the present invention, the second cooling unit group and the remaining cooling unit of the first cooling unit group are disposed so that they face each other. With this arrangement, the whole of the cooling units can be made compact. In addition, the cooling efficiency can be enhanced with the single cooling fan, and the operation cost can be reduced.
In the construction machines of the present invention, a gap is provided between the second cooling unit group and the remaining cooling unit so that cleaning can be performed. With this arrangement, dust and dirt on the cooling units can be easily cleaned, for example, by inserting an air jet nozzle into the gap.
In the construction machines of the present invention, a gap-closing cover is provided to nearly close at least the circumference of the gap and is rotatable or detachable. This can prevent a reduction in the cooling efficiency due to the leakage of the cooling air from the gap. In the case where the rotatable or detachable gap-closing cover is used, the cooling efficiency can be enhanced. In addition, in cleaning the cooling units, the rotatable or detachable gap-closing cover is rotated or removed, and dust and dirt on the cooling unit can be easily cleaned, for example, by inserting an air jet nozzle into the gap.
In the construction machines of the present invention, the gap D between the second cooling unit group and the remaining cooling unit of the first cooling unit group disposed so as to face the second cooling unit group is set so that a ratio of the gap D to a height H of a cooling unit of the second cooling unit group on the upstream side of the remaining cooling unit is D/H=0.05 to 0.3. With the ratio D/H, a degree of freedom in designing the gap D and the height H can be increased and the gap D and the height H can be suitably disposed according to design specification.
In the first and second construction machines of the present invention, the gap D is set to about 30 to 300 mm, preferably about 40 to 100 mm. Because of this, there is an effect that the cooling units can be easily set according to design specification by the gap D.
In the construction machines of the present invention, the cooling unit of the second cooling unit group on the upstream side of the remaining cooling unit comprises an intercooler. This makes it possible to easily perform cleaning of the cooling units including the intercooler.
In the construction machine of the present invention, the nearly sealed engine room section is constructed so that cooling air introduced by the cooling fan is drawn in, or is constructed so that it is ventilated by discharging the cooling air within the nearly sealed engine room section, which has risen in temperature, from blowoff bores of the partition member with the cooling air introduced by the cooling fan.
With this construction, the leakage of noise from the engine to the outside can be effectively reduced.
In the first and second construction machines of the present invention, the cooling fan comprises an axial flow fan, a bent axis flow fan, or a centrifugal fan. Therefore, by suitably using an axial flow fan, a bent axis flow fan, or a centrifugal fan, the cooling efficiency can be enhanced and the cooling fan can be made compact.
In the construction machines of the present invention, the nearly sealed engine room section is provided with an ejector. With the ejector, cooling within the nearly sealed engine room section can be efficiently performed.
In the construction machines of the present invention, the nearly sealed engine room section is provided with an ejector and a ventilating fan. The synergetic effect of the ejector and the ventilating fan can enhance the cooling effect within the nearly sealed engine room section.
The construction machine of the present invention further comprises cylindrical guide members which have a communicating bore corresponding and communicating with a communicating bore or blowoff bore provided in the partition member. The cylindrical guide members make it possible to enhance the cooling effect within the nearly sealed engine room section.